Fig. 1. A multichannel, fMRI-compatible, spectrally resolved, fiber photometry platform used to measure coupling of neuronal signals between the AI, Cg, PrL, and RSC.

(A) Schematic illustration of the photometry system used for measuring GCaMP signals in four distinct brain areas concurrently with fMRI. (B to E) Spontaneous, resting-state, GCaMP signal fluctuations in AI, Cg, PrL, and RSC in anesthetized rats. Representative GCaMP time-frequency plots and corresponding average GCaMP power spectra (n = 7) were plotted for each region, respectively. Prominent spectral power below 1 Hz was found in all photometry recording sites. (F) Partial correlations between GCaMP activity recorded from the AI, Cg, PrL, and RSC included significant positive correlations between the AI and Cg, the Cg and PrL, and the Cg and RSC. Data are presented as box and whisker plots, where boxes encompass values between the 25th and 75th percentiles, and horizontal lines represent median values. Dots in the figure represent the correlation coefficients of each individual rat. *P < 0.05, n = 7, two-tailed t test, false discovery rate (FDR)–corrected. (G) Dendrogram from hierarchical analysis of the strength of functional connectivity shown in Fig. 1F.